Histologic Variations of Intramural Heterotopic Pancreas in Gastrointestinal Tract Analysis of 15 Cases

Lee, Seung Sook; Kim, Yong Il; Kim, Woo Ho; Yu, Eun Sil

Abstract

We reviewed a total of 15 cases of heterotopic pancreatic tissue within the gastrointestinal wall(intramural type), and compared with 3 extramural ones. Intramural heterotopic pancreatic lesions were located in the antrum(33%), pylorus(20%), and body of stomach(7%), and the remainders in the duodenum(40%). Only two cases presented with chinical symptoms by their existence. Two of them were situated within the submucosa, 3 in the muscularis, 6 in submucosa-muscularis, 2 in the muscularis-subserosa, and 1 in the susbmucosa-subserosa. Intramural type was featured with their structural heterogeneity compared to the extramural ones; 10 cases showed participation of gastrointestinal mucosal elements, and some accompanied tissue elements that were indistinguishable from submucosal epithelial heterotopia or microduplication cyst of the stomach. Langerhans islets were found in 67%, and one developed islet cell tumor. The above results suggest that the initially engrafted heterotopic pancreatic tissue becomes modified and presents with heterogeneity of endodermal and mesodermal tissue-derived components by its intramural growth during the gastrointestinal organogenesis; failure of opening of its drainage system into the gastrointestinal lumen may result in the increase of intraductal pressure with subsequent atrophy of the acinar tissue and various metaplastic changes of ductal epithelium, aside from induction of smooth muscle coat around the heterotopic tissue.